LOVERS, by Brian Friel; directed by Tim Truby; designed by Tom Chapman-Loftis; produced by Bart Whiteman; with Kathleen Weber, Jon Helmrich, David Mosedale, Judith Benedict, Madge Daly and Bernie Horowitz. At the Source Theater through Oct. 19.

"If that couch could talk!" exclaims a character in "Lovers," reminiscing about his living-room courtship of the woman who later became his wife.

The couch never does talk, but if anyone could put a talking couch on stage, it would be Brian Friel, the Irish author of the two one-acters with the single title that opened at the Source Theater Thursday night. To Friel, a play is scarcely a play without an absolutely unprecedented gimmick that sounds outrageous and unworkable. In "Philadelphia Here I Come," the gimmick was a leading character played by two different actors -- a good and bad self, as it were. In "The Faith Healer" it was three characters who spoke to the audience but never to each other.

And in the first half of "Lovers," Friel has two narrators sitting on stage reciting newspaper stories about the drownings of a boy and girl whom we see -- in simultaneous flashback -- alive and well and preparing to be married. s

Meg and Joe, both 17, live in Ballymore, County Tyrone, Northern Ireland. Meg is pregnant, full of fanciful notions, and inclined to say whatever comes into her mind. Joe, more sober and studious, vacillates between professions of love and spiteful accusations that she has "trapped" him into marriage. Despite their contrasting personalities, each is trying to be in love without wanting to understand the other.

With Friel's flair for rich , country-Irish dialogue on their side, Meg and Joe are a fascinating pair -- until it gradually becomes clear that the playwright has nowhere to take them (except to their deaths). And even then, Kathleen Weber gives a compelling performance as the artful, rhapsodic, nonstop-talking Meg. Jon Helmrich is smooth, if less varied, as Joe, although it would be difficult for any actor to make this character's sudden shift from reticence to volubility entirely credible. In having Meg and Joe reverse moods as they do, Friel seems to have gone for irony and symmetry at the expense of integrity.

But up until the last 15 minutes or so, this half of the bill is utterly absorbing. The second play is shorter and, within its more limited ambitions, thoroughly satisfying. Here we have a husband recollecting the days when he courted his wife downstairs while his invalid, ultra-religious mother-in-law-to-be lay in bed upstairs, scheming to keep the future newlyweds forever on the premises.

This play -- and especially the sequence in which the hero triumphantly exposes the old lady's favorite saint as apocryphal -- is extremely funny. The cast is only slightly less so. Both plays have been nimbly directed by Tim Trubly, and profit from simple but evocative scenery by Tom Chapman-Loftis.